Transition metal metallocene compounds are useful as olefin polymerization catalysts in conjunction with cocatalysts such as aluminoxanes. These catalysts can advantageously produce olefin polymers with narrow molecular weight distributions, homogeneous comonomer distributions, and good processability.
However, the cost of such catalysts is higher than traditional Ziegler-Natta catalysts, due in part to the complex synthesis methods required to make them. Metallocene precursors are usually synthesized through transmetallation reactions, as illustrated in Scheme I (using the compound bis(indenyl)dimethylsilane as an example).